Raised Veggie Bed

Asked July 29, 2015, 10:43 AM EDT

Hello, I am hoping to build a raised bed for the fall. What type of wood is typically used for a raised garden bed? I know cedar might be most durable but its also very pricey. Is pressure treated wood safe? Thanks!

Baltimore County Maryland

1 Response

This will continue to be a somewhat controversial issue. The relatively new chemical treatment- ACQ (alkaline copper quaternary) does not contain arsenic or chromium, the two elements of concern used in the discontinued CCA treated lumber. According to the U.S. EPA: All ACQ types contain 2 active ingredients which may vary within the following limits: copper oxide (62%-71%), which is the primary fungicide and insecticide, and a quaternary ammonium compound (29%-38%), which provides additional fungicide and insect resistance properties.

Some of the copper may leach over time from the lumber, but the risk to human health is considered to be low. From the research that we have seen, a toxic level of copper would kill the plants before the edible fruit, roots, or plants would be harvested. If you have doubts, select a different material such as concrete blocks, brick, stone, and untreated or plastic lumber. You could forego any enclosure by mounding the soil 4-6 inches above grade, leveling the top and sloping the sides.